1476-23-9Relevant academic research and scientific papers
Supporting-Electrolyte-Free Anodic Oxidation of Oxamic Acids into Isocyanates: An Expedient Way to Access Ureas, Carbamates, and Thiocarbamates
Petti, Alessia,Fagnan, Corentin,van Melis, Carlo G. W.,Tanbouza, Nour,Garcia, Anthony D.,Mastrodonato, Andrea,Leech, Matthew C.,Goodall, Iain C. A.,Dobbs, Adrian P.,Ollevier, Thierry,Lam, Kevin
supporting information, p. 2614 - 2621 (2021/06/27)
We report a new electrochemical supporting-electrolyte-free method for synthesizing ureas, carbamates, and thiocarbamates via the oxidation of oxamic acids. This simple, practical, and phosgene-free route includes the generation of an isocyanate intermediate in situ via anodic decarboxylation of an oxamic acid in the presence of an organic base, followed by the one-pot addition of suitable nucleophiles to afford the corresponding ureas, carbamates, and thiocarbamates. This procedure is applicable to different amines, alcohols, and thiols. Furthermore, when single-pass continuous electrochemical flow conditions were used and this reaction was run in a carbon graphite Cgr/Cgr flow cell, urea compounds could be obtained in high yields within a residence time of 6 min, unlocking access to substrates that were inaccessible under batch conditions while being easily scalable.
Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
, p. 15890 - 15895 (2021/05/19)
A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
Method for preparing isocyanate-based silane by hydrosilylation reaction
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Paragraph 0020; 0022; 0024; 0026, (2019/10/01)
The invention relates to a synthetic method of an isocyanate-based silane coupling agent and belongs to the field of synthesis of silane coupling agents. The preparation method comprises the followingsteps: taking allyl urea and sodium nitrite as main raw materials, taking toluene as a solvent, and taking tetra-n-butyl ammonium bromide as a catalyst to synthesize allyl isocyanate; then, under theaction of a noble metal catalyst such as platinum or rhodium, carrying out hydrosilylation with silicon-hydrogen bond containing hydrogenalkoxysilanes such as trimethoxy silane, triethoxy silane andthe like for carrying out a reaction to generate an isocyanate-based silane coupling agent crude product; and then carrying out reduced pressure distillation treatment to obtain the isocyanate-based silane coupling agent product. The method has the advantages of simple operation, high reaction conversion rate, high yield, stable quality, safe environment-friendly energy-saving efficient productionprocess, and the like, and industrial production is easy to realize.
Organosilicon synthesis of isocyanates: II. Synthesis of aliphatic, carbocyclic, and fatty-aromatic isocyanates
Lebedev,Lebedeva,Sheludyakov,Ovcharuk,Kovaleva,Ustinova
, p. 469 - 477 (2008/02/07)
Silylation of a series of aliphatic, carbocyclic, and fatty-aromatic amines gave the corresponding silyl derivatives whose yield depended on the electronic and steric structure of the substrate and the nature of the silylating agent. The yield of isocyanates obtained by phosgenation of the silyl derivatives under mild conditions decreased in going from aliphatic amines to benzylamines and rose as the length of the alkyl chain in fatty-aromatic amines extended. The most convenient procedure for the synthesis of low-boiling alkyl isocyanates was found to be based on the transformation of amines or ammonium salts into silyl or silyl silyl-carabamates, followed by pyrolysis of the latter in the presence of trichloro(phenyl)silane. Pleiades Publishing, Inc., 2006.
The first direct observation of an allylic [3,3] sigmatropic cyanate-isocyanate rearrangement
Banert, Klaus,Melzer, Antje
, p. 6133 - 6135 (2007/10/03)
Evidence is presented that the [3,3] sigmatropic rearrangement of simple allyl cyanates to give allyl isocyanates proceeds much more rapidly than the analogous reaction of propargyl cyanates. Nevertheless, a substituted allyl cyanate is isolated for the first time, and the activation parameters of its [3,3] sigmatropic isomerization are measured.
Importance of the lipophilic group in carbamates having histamine H3- receptor antagonist activity
Kiec-Kononowicz,Wiecek,Sasse,Ligneau,Elz,Ganellin,Schwartz,Stark,Schunack
, p. 349 - 355 (2007/10/03)
In order to evaluate changes in the lipophilic part of designed carbamates concerning their potential histamine H3-receptor antagonist properties a new series of O-[3-(1H-imidazol-4-yl)propanol]carbamates was derived containing N-mono- or dialkenyl, alkynyl, cycloalkyl, or double- branched alkyl substituents. The compounds were tested in vitro for their H3-receptor antagonist activity on synaptosomes of rat cerebral cortex and shared moderate to high antagonist activity in vitro. In this series 3-(1H- imidazol-4-yl)propyl N-(4-pentenyl)carbamate (4) was the most potent compound in vitro (K(i) = 6.3 nM). H3-receptor antagonist activity in the central nervous system (CNS) was detected for most compounds in the in vivo H3- receptor assay based upon measurement of brain N(τ)-methylhistamine levels after p.o. administration to mice. The most effective carbamate in vivo, 3- (1H-imidazol-4-yl)propyl N-(allyl)carbamate (3), showed higher CNS potency (ED50 = 0.48 mg/kg p.o.) than the reference antagonist thioperamide. For some novel carbamates their histamine H1- and H2-receptor activities were determined on isolated organs of guinea-pig thereby demonstrating their high H3-receptor selectivity.
Heterocyclic compounds having MMP and TNF inhibitory activity
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, (2008/06/13)
Compounds of formula (I) are useful as therapeutic agents, by virtue of having MMP and TNF inhibitory activity.
